Power converting devices are used in power generation for adapting, particularly matching the variable voltage, variable frequency and changing power characteristics of the generating device to the generally fixed frequency and fixed voltage characteristics of the power network or grid.
Conventionally, a power converting device comprises at least one voltage converting unit which is adapted to convert AC voltage signals of different phases to DC voltage signals of different phases or vice versa. Further, the power converting device comprises at least one inter-phase transforming unit which is adapted to operate on the voltage signal of the power converting unit. Common nodes are used for combining transformed voltage signals outputted by the inter-phase transforming units. In the use of the inter-phase transforming units, each of the typically three phases of the total power converting device themselves each have sub-phases that are combined with the inter-phase transforming system.
U.S. Pat. No. 5,852,554 discloses a power inverter comprising first, second, and third power inverting units and first, second, and third inter-phase reactors. The power inverting units are arranged and constructed to be adapted to be driven in parallel. Each of the inverting unit outputs first, second, and third voltage signals with the phases of the first, second, and third voltage signals of one of the inverting units being different to one another and with first, second, and third voltage signals of different inverting units being identical to one another, respectively. Each of the inter-phase reactors is adapted to operate on the voltage signals of identical phases and comprises three inter-phase transforming units, namely three coils. Each of the coils of one of the inter-phase reactors is electrically connected to one different output of the power inverting unit. The transformed first, second, and third voltage signals of identical phases are combined such that first, second, and third output voltage signals are generated. The combination of three voltage sources for a given phase results in a single phase output voltage that is directed at the load which may be a generator or a network, respectively.
WO 2008/030919 A2 discloses a multiphase converter which comprises first, second, and third switching cells being in parallel electrical connection to one another. Each of the switching cells is adapted to output a voltage signal of a different phase. Each of these first, second, and third voltage signals of different phases are fed to one different of first, second, and third transformers. Each of the first, second, and third transformers comprises two coils being magnetically coupled to one another. Transformed first, second, and third voltage signals output by the first, second, and third transformers are averaged and fed to a common node such that an output voltage signal of a single phase is generated. This is repeated for each of the typically three phases in the complete power converting device.